As per mmc-pwrseq-simple.yaml, the correct way to describe the GPIO
is by using the 'reset-gpios' property.
Change it accordingly to fix the following schema warning:
imx8mq-thor96.dtb: sdio-pwrseq: 'gpio' does not match any of the regexes: 'pinctrl-[0-9]+'
from schema $id: http://devicetree.org/schemas/mmc/mmc-pwrseq-simple.yaml#